Power operated lawn mowers typically have a shroud with depending sides that extend over and surround the rotating cutter blades within the shroud. Typically, the shroud is fitted with a discharge chute through which the cut grass exits to be either passed to a collection container for later disposal, or is deposited on the lawn in the form of mulch. In certain areas, however, it is imprudent to leave the discharge chute open; such situations exist when the lawn mower is being used near buildings or around people, as small stones or other dangerous objects may be discharged at a relatively high velocity, causing damage or injury.
To counter this problem, the prior art has developed a number of techniques for permitting the discharge chute to be alternately opened and closed in a relatively rapid manner. Examples of such prior art arrangements are disclosed below. As more fully explained herein, these arrangements suffer from various drawbacks.
U.S. Pat. No. 4,135,351 to Akgulian discloses a rotary lawnmower grass mulcher assembly having a mower housing and a discharge opening covered by a pair of plates having air holes there through. The air holes are offset between the two plates, which allows for the discharge of air while maintaining the grass clippings in the mower housing for mulching.
U.S. Pat. No. 4,45,312 to Cartner discloses a mower head with movable guard for an articulated boom assembly attached to a mow tractor. The movable guard may be opened via a hydraulic means for allowing the mower blade to cut saplings and the like.
U.S. Pat. No. 5,040,364 to Deegan discloses a lawnmower having a selectable discharges means. The lawnmower described comprises a cutting deck having a plurality of discharge exit ports, each covered with a closure means. Each closure means is connected to a control lever, which operates to open and close the closure means via a cable attachment.
U.S. Pat. No. 5,048,279 to Badawey et al. discloses a leaf mulcher for use with a rotary blade power lawnmower. The leaf mulcher comprises a screen, which covers the outlet of the lawnmower. The screen is offset to provide a space between the outlet and the screen thereby allowing a portion of the grass clippings to escape from outlet without passing through the screen.
U.S. Pat. No. 5,133,175 to Dumbrell discloses a safety flap for power-operated lawnmower the apparatus remains in the closed position due to the force of gravity.
U.S. Pat. No. 5,284,007 to Poe et al. discloses a mulching and shredding attachment for the use on a lawnmower or lawn vacuum, which is held in place by a bracket comprising a lever and a clevis pin. Removal of the pin allows for the apparatus to be engaged or disengaged.
U.S. Pat. No. 5,657,620 to Thagard et al. discloses a device for mowing, cutting and mulching. The device is generally attached to a tractor power drive, and comprises a shroud mechanism that may be mechanically opened. When the shroud mechanism is mechanically opened it exposes the cutting means for removing brush and saplings.
Finally, U.S. Pat. No. 5,826,417 to Evans discloses an operator control deflector plate for the discharge chute of a riding lawnmower. The deflector plate comprises a series of air holes large enough to allow the passage of grass, however, small enough to prevent the passage of objects sufficient to cause physical injury or property damage. The device may be selectively opened by a lever mechanism mounted to the lawnmower cutting deck.
Despite these prior art efforts, there remains a need for discharge chute opening and closing apparatus that is rugged and operates to quickly move the cover for the discharge chute between the open and closed positions. All documents and publications cited are incorporated by reference to the extent not inconsistent with the explicit teachings set forth herein.